Differential Diagnosis

The patient's presentation of crossed adductor reflex with cerebellar signs, dysdiadochokinesia on the left hand, inability to perform smooth pursuits, and a positive Romberg's test suggests a complex neurological condition. Here's a categorized differential diagnosis:

• Single Most Likely Diagnosis

  • Cerebellar Stroke or Infarct: The combination of cerebellar signs (dysdiadochokinesia, difficulty with smooth pursuits) and the presence of a crossed adductor reflex, which can indicate an upper motor neuron lesion, points towards a cerebellar lesion. A stroke or infarct in the cerebellum could explain these findings, especially if there's evidence of brainstem involvement affecting cranial nerve nuclei responsible for eye movements.

• Other Likely Diagnoses

  • Multiple Sclerosis (MS): MS can present with a wide range of neurological symptoms, including cerebellar signs, upper motor neuron signs (like the crossed adductor reflex), and difficulties with coordination and balance. The optic neuritis or brainstem lesions in MS could also explain the inability to perform smooth pursuits.
  • Spinocerebellar Ataxia (SCA): This is a group of genetic disorders characterized by progressive cerebellar ataxia. Some forms of SCA can present with a combination of cerebellar signs, upper motor neuron signs, and difficulties with eye movements, including smooth pursuit.
  • Cerebellar Degeneration: Conditions like alcoholic cerebellar degeneration or other toxic/metabolic cerebellar degenerations could explain the cerebellar signs. However, the presence of a crossed adductor reflex might suggest a more complex pathology.

• Do Not Miss Diagnoses

  • Brainstem Tumor: A tumor in the brainstem could explain the combination of cerebellar signs, upper motor neuron signs, and difficulties with eye movements. Given the potential for serious complications, including hydrocephalus or brainstem compression, this diagnosis is critical not to miss.
  • Infectious or Inflammatory Conditions (e.g., Abscess, Encephalitis): Conditions like a brain abscess or encephalitis, particularly those affecting the cerebellum or brainstem, could present with a wide range of neurological symptoms, including those described. These conditions require prompt diagnosis and treatment to prevent serious complications.
  • Vitamin B12 Deficiency: While less likely to cause all these specific symptoms, a vitamin B12 deficiency can lead to subacute combined degeneration of the spinal cord, affecting both the dorsal columns and the corticospinal tracts, potentially causing ataxia, upper motor neuron signs, and balance difficulties.

• Rare Diagnoses

  • Paraneoplastic Cerebellar Degeneration: This is a rare condition associated with certain cancers, where the immune system mistakenly attacks the cerebellum, leading to progressive cerebellar ataxia and potentially other neurological symptoms.
  • Ataxia-Telangiectasia: A rare genetic disorder that affects the nervous system, immune system, and other bodily systems, characterized by cerebellar ataxia, oculocutaneous telangiectasias, and a predisposition to cancer.
  • Creutzfeldt-Jakob Disease: A rare, degenerative, fatal brain disorder that can present with ataxia, dementia, and myoclonus, among other symptoms. While the described symptoms don't perfectly align with typical presentations, the disease's rarity and severity warrant consideration in complex neurological cases.